The 5-man news really was expected, but the raid info is much more exciting:

All raid dungeons will have both 10-man and 25-man versions

The 10 and 25-man progressions will not depend on each other

There will be no attunements or keys necessary for any raid

The 25-man loot will be a tier higher than the 10-man loot

The 10 and 25-man versions of the same raid will be on different timers so that each can be attempted on the same day by the same people

It seems that Blizzard is trying to make both the hardcore and casual raiders happy with these changes. Those guilds who can only see the 10 man content will be able to see all of the endgame content, but those who can organize 25 person raids will reap the benefits of the most challenging content and best gear in the game. And group instances that only take an hour will be great for those of us with limited playtime.